Method of, and apparatus for, die casting metals



G. NYSELIUS Aug. 24, 1965 METHOD OF, AND APPARATUS FOR, DIE CASTING METALS Filed Sept. 2l. 1964 Gasm/ Wyse/us United States Patent O 3,201,836 METHOD OF, AND APPARATUS FOR, DIE CASTING METALS Gustav Nyselius, Stamford, Conn., assigner to Mount Vernon Die Casting Corporation, Stamford, Conn. Filed Sept. 21, 1964, Ser. No. 398,126 2 Claims. (Cl. 22-68) This invention relates to improved apparatus for die casting, the presentvapplication for letters patent thereon being a continuation-impart of my application S. No. 225,412, filed September 19, 1962, in turn a continuationin-part of my application S. N. 176,262, filed February 28, 1962, both now abandoned. While the herein apparatus is applicable to casting of any metal, it is particularly valuable whenA applied to the casting of aluminum, as will hereinafter appear.

The purpose of the invention is to eliminate slag format-ion during casting i.e. to prevent the 4formation of a plug and other waste met-al While forming the desired casting.

Die casting operations as now and previously practiced lare very inecient since for each casting operation a great deal of casting material .is solidified in addition to the desired casting. This additional solidified material is waste and must be separated from the desired casting Iand collected and remelted. In apparatus in use at the present -time for casting aluminum a plug of metal solidifies at the front end of the sleeve and is integral with the metal solidifying in the runner cavity, the gate cavity and the die cavity. The amount of waste metal so cast is often as much as 50% of the metal usefully cast in the die. It must, of course, be separated from the desired casting, i.e., the aluminum which solidies in the die, and separately collected in containers which must be stored and eventually transported to a melting furnace '-to be remelted and resuppl-ied to the `casting machines.

When it is considered that a large proportion of this separated, stored, transported 'and remelted casting material will again be solidified outside the die cavity and will again have to be separated from the desired casting, separately collected and stored and transported to the melting furnaces and remelted, and that a portion of the remelted casting material will go through the same steps again and again, it becomes apparent how inetlicient are :the present method and apparatus.

In the prior art are die casting machines which for one reas-on or :another supply molten metal to a charging sleeve from a reservoir disposed below the sleeve, and intermittently force a charge of metal from the sleeve through a runner .into a die cavity located above the sleeve. However no excess aluminum can be returned rfrom the runner by gravity since a plug forms which seal-s the runner from the cavity.

In the operation of the apparatus described herein no plug is formed and all molten `aluminum supplied from a reservoir for a casting operation is returned to the reservoir between casting cycles This makes it practical to use a steel charging sleeve. It would not be practical t do so unless the molten aluminum is returned between cycles for a steel sleeve would be damaged and eventually Iruined by continuous contact with molten aluminum,

The invention will best be understood by reading the following description .in connection with the drawings f in which:

10, formed between die plates 12 and 14, from a cylinice drical charging sleeve 16, through the nipple 18. Die plate 12 is supported on stationary die platen 12a and die plate 14 is supported on movable platen 14a. The sleeve 16 extends through platen 12a and its projecting rear end is received in the recess 14b in platen 14a when the -platens are together Vand the die cavity is closed. The -rear end of the -sleeve is closed by the end wall 16b. The vertical 4center line or axis of nipple 18, which projects radially from the sleeve adjacent its closed end to the die cavity and thus communicates between the sleeve 16 and the die cavity, is aligned with the line of parting p of the die plates 12 and 14. To accommodate the nipple 18 in this position, the adjacent faces ofthe die plates 12 and 14 are complementally cored out or otherwise recessed to seat said nipple. l

Disposed around the full length of sleeve 16 is a heating coil 20 which is employed to keep the interior of sleeve 16 heated sufliciently to maintain the casting material therein in molten state. Surrounding the sleeve and the heating coil is the insulation 22. The placement of nipple 18 short of the closed end of the sleeve 16 as shown also results in the nipple being similarly heated by the heating coil 2t).

With-in sleeve 16 a `charging piston 24 is provided, which may be of any known, suitable kind and reciprocated in any known, suitable way in timed rel-ation to the opening and closing of the platens 12a and 14a.

It is conventional in the type of machine in connection with which is illustrated an embodiment of this invention to reciprocate both the movable die platen 14a and the charging piston 24 by means of hydraulic pressure operated by known timing mechanism, and such means is not illustrated herein since it is well known yIn FIG. 1 the charging piston 24 is shown fully retracted, at the end of its stroke, and it will be noted that its head portion 24a is just behind the groove 26 provided in the inner surface of sleeve 16. A conduit 28 eX- tends between reservoir 30 and groove 26 and casting material is supplied from the reservoir into the charging sleeve 16 through conduit 28, by pressure applied within reservoir 30 as through the air line 32, or alternatively by reduced pressure applied through the vacuum line 34 and communicated to reservoir 30 through the zig zag eX- haust gate 36, die cavity 10, nipple 18, the sleeve 16, groove 26 and conduit 28. It will be understood that the application of pressure within reservoir 30` will be controlled by suitable means, such as, for example, the solenoid valve 38 shown in connection with the pressure line 32 to operate in timed relation with the cycle of oper-ation of the casting machine.

If the Vacuum line 34 is used it will be actuated only after the die plates are closed, and when the charging piston is in its fully retracted position, and it will be cut 01T `by the hardening of casting material in the zig zag exhaust gate. If the pressure line 32 is employed it will be actuated only after the die plates are closed, and when the charging piston is in its fully retracted position, and and it will be cut ofr" when the piston has advanced suflciently to cover groove 26.

I have successfully supplied casting material from a reservoir such as 30, through a supply line such as 28, into a horizontally disposed charging sleeve such as 16, by supplying a pressure of only 16 oz. through line 32.

It will be understood that in the operation of the apparatus shown in FIGS. 1 and 2 part of the casting Inaterial supplied into sleeve or cylinder 16 will be forced through nipple 18 from sleeve 16 into die cavity 10 by the forward movement of the charging piston 24. Upon the return stroke of the piston the casting material in nipple 18 falls back into sleeve 16, and from -sleeve 16 the casting material will return by gravity through groove 26 and conduit 28 into the reservoir 30.

eliminating the formati-on of -a plug, any excess aluminum t 'below the die cavity is returnedrto the reservoirbetween charging cycles.

There hasrthus been provided'a method andl apparatus in which 4the above mentioned Iobects have been provided in a ,thoroughly practical manner; What I claim is:

1. Apparatus for die casting metal which comprises: y

a stationary die plate and a mov-able :die platefwhich when their relatively inner faces are'closed together dene a die cavity, the stationary die plate having an yopeningV extending transversely through vit directly below the die cavity, `and the'movabledie Vplate having a recess in its relatively inner face extending in continuation ofthe openingv inthe stationary die plate,` aV sleeve klixedly dis- Y posed in the opening in the stationary die plate andy hav ing a closed forward end portion' projectingY beyond the relatively inner facey of the station-ary die', plate and adapted to move into thessaid recess inthe corresponding the melting point of thecasting material, a reservoir for metal casting material disposed below said sleeve,-and means forintermittently `raising a charge of casting material from the Vreservoir to the die cavity including a conduit communicating between the reservoir and the rearward 4end portion ofthe sleeve and va charging piston reciprocable within the sleeve to force a charge of casting material from the sleeve through Asaid Ynipple to fill the cavity, the'conduit communicating to the sleeve at a point alongtheV length thereof which is so'located that when theplunger is atv the rear end' of its stroke the conduit connection to the reservoir is uncovered, thus allow- Y ing molten metal in theheated nipple andsleeve. to reinner` face of the movable die plate when the'die plates are closed togethep a short-length nipple aix'edto Iand projecting radially from said forward end portion of said sleevefto the Adie cavity and communicating "directly between the sleeve and the die cavity, the axis of the nipple Y being aligned- With the line of' partiti-ingV between the die turn to thel reservoir by gravity after eachreciprocation of the plunger.

2. Apparatus according t-o claim Y1,-wherein thernolten metal beingcast is aluminum and the sleeve is fashioned from steel; Y'

References Cited by'theExaminer Y i I Y' UNITED STATES PATENTS s j '2,131,955 10/-38 Johnson` p t 2'2-59 2,393,588 y1/46 Cherry A227-70 12,660,769V 12V/52V Bennett Y v r 22-209 12,955,335 `l0/60 Morgensterne 22-68 .2,985,9281' .5/61 .Heskett 2267 13,009,218 1v1/'61"'Rearwin 22-68 Moore n, r 22--68 plates and the lnner faces of said d1e" plates being com-I 30 M ARGUS UIV LYONS Pfrismy Examiner.

plemental'ly recessed to provi-de a full'tubular seat for said nipple, means extending the full length'of'isaid sleeve for maintainingthe sleeve andfnipple at atemperaturegabove WILLIAM, LSTEPHENSON, Examiner. v 

1. APPARATUS FOR DIE CASTING METAL WHICH COMPRISES: A STATIONARY DIE PLATE AND A MOVABLE DIE PLATE WHICH WHEN THEIR RELATIVELY INNER FACES ARE CLOSED TOGETHER DEFINE A DIE CAVITY, THE STATIONARY DIE PLATE HAVING AN OPENING EXTENDING TRANSVERSELY THROUGH IT DIRECTLY BELOW THE DIE CAVITY, AND THE MOVABLE DIE PLATE HAVING A RECESS IN ITS RELATIVELY INNER FACE EXTENDING IN CONTINUATION OF THE OPENING IN THE STATIONARY DIE PLATE, A SLEEVE FIXEDLY DISPOSED IN THE OPENING IN THE STATIONARY DIE PLATE AND HAVING A CLOSED FORWARD END PORTION PROJECTING BEYOND THE RELATIVELY INNER FACE OF THE STATIONARY DIE PLATE AND ADAPTED TO MOVE INTO THE SAID RECESS IN THE CORRESPONDING INNER FACE OF THE MOVABLE DIE PLATE WHEN THE DIE PLATES ARE CLOSED TOGETHER, A SHORT-LENGTH NIPPLE AFFIXED TO AND PROJECTING RADIALLY FROM SAID FORWARD END PORTION OF SAID SLEEVE TO THE DIE CAVITY AND COMMUNICATING DIRECTLY BETWEEN THE SLEEVE AND THE DIE CAVITY, THE AXIS OF THE NIPPLE BEING ALIGNED WITH THE LINE OF PARTING BETWEEN THE DIE PLATES AND THE INNER FACES OF SAID DIE PLATES BEING COMPLEMENTALLY RECESSED TO PROVIDE A FULL TUBULAR SEAT FOR SAID NIPPLE, MEANS EXTENDING THE FULL LENGTH OF SAID SLEEVE FOR MAINTAINING THE SLEEVE AND NIPPLE AT A TEMPREATURE ABOVE THE MELTING POINT OF THE CASTING MATERIAL, A RESEVIOR FOR METAL CASTING MATERIAL DISPOSED BELOW SAID SLEEVE, AND MEANS FOR INTERMITTENLY RAISING A CHARGE OF CASTING MATERIAL FROM THE RESEVIOR TO THE DIE CAVITY INCLUDING A CONDUIT COMMUNICATING BETWEEN THE RESIVIOR AND THE REARWARD END PORTION OF THE SLEEVE AND A CHARGING PISTON RECIPROCABLE WITHIN THE SLEEVE TO FORCE A CHARGE OF CASTING MATERIAL FROM SLEEVE THROUGH SAID NIPPLE TO FILL THE CAVITY, THE CONDUIT COMUNICATING TO THE SLEEVE AT A POINT ALONG THE LENGTH THEREOF WHICH IS SO LOCATED THAT WHEN THE PLUNGER IS AT THE REAR END OF ITS STROKE THE CONDUIT CONNECTION TO THE RESEVIOR IS UNCOVERED, THUS ALLOWING MOLTEN METAL IN THE HEATED NIPPLE AND SLEEVE TO RETURN TO THE RESERVIOR BY GRAVITY AFTER EACH RECIPROCATION OF THE PLUNGER. 